> I´ve run Btree based HPFS for over a decade... > http://pages.cs.wisc.edu/~bolo/shipyard/hpfs.html
HPFS is for the most part a traditional Unix file system with cylinder groups. You have superblock (block 16), and then 8MB bands of data with allocation bitmaps between them. Sound familiar ? It also does pre-allocation and give back (as ext3/4 now do with reservations) but has no journalling. So its really a BSD FFS like file system with fancier metadata. That's completely different to a b-tree/b+tree file system like reiserfs3 or btrfs. In particular it uses btrees within objects only. So corrupting the btree of an FNODE loses you a file and your coherency checking problem for the tree is internal to each object. A DIRBLK is perhaps slightly worse news but you've still got the FNODE so you can find the contents of everything. Apple HFS/HFS+ has a similar sort of design. Ask any long term MacOS user about the dreaded "Invalid B-tree node" message which is usually followed by "Error: File system verify or repair failed" Alan -- users mailing list users@lists.fedoraproject.org To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
